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162" Art Scholl Super Chipmunk

Hey Guys, Well I've been gathering info for sometime now. I have decided it was time to start the build. This build will be a slow one, as I'm still needing a few things.

This is my first scratch build and the first time I've ever worked from enlarged plans. The plans are the old Ohio RC plans (81") that where doubled. Power will be a DA-150 with cans if they can be made to fit. 12 servos should do the job. I will also have smoke. I'm estimating the weight around 60lbs.

I will be making a few mods from the plans. I'm not trying for perfect scale just going to try and get rid of the Sport scale look of the plans. The wings will be built as is. I've talked with several builders that say the wing is a good airfoil. I will be making it a three peice wing though. It will break at the ailerons.

The fuse will be rounded out. The Ohio kit had very flat sides and no wing fillets.

The first pic is of the main spar. It is two 1/4"x48" plywood.

Second is of the bottom spar. I cut a groove in it with my table saw. This will make the shearwebs stronger.

Pic three is of the lightning hole cut in to a 1/8" ply rib. There are only five of these.

Pics 4 and 5 are of the wing tube holes.

And finally the wing test fitted together. No Glue yet.

That is a 36" yard stick laying on the wing.

More pix later.
Kelly

Attached Thumbnails

Greg Norman said, \"Happiness is a long walk with a putter.\" Obviously he never flew a P-51 Mustang.

RE: 162

Hey Rick, I'm just guessing.[8D] It will be fully sheeted and glassed with paint. I'll say 60 so that way if it is lighter, that will be a plus. It will still have good performance even at 60lbs.

I have been weighing all the pieces that have been lightened. So far I've saved about 2.5 lbs. Most of that was plywood weight. Now I'm in the lite ply pieces, so there won't be much weight to lose.
Today I lightened some of the lite-ply ribs. So far on rib 7 I saved 1.2 ozs and on 8 about 1.5.( for both wing panels) As long as I can see a meaningful weight reduction, I will lighten more of the lite-ply ribs.

Later,
Kelly

Greg Norman said, \"Happiness is a long walk with a putter.\" Obviously he never flew a P-51 Mustang.

RE: 162

I finally lightened all the ribs. In all I removed a 1/2 lb. That is for both wing panels. Didn't cut number 14. Every little bit adds up.

I have the lite-ply shear webs cut and they lock in place tight. Tomorrow after I sleep on it some, it will get some glue.

I did have to replace the inner rib 6. (that's the break) It was off just a tad. Didn't want it to bite me later. After some careful measuring I saw it was off more than I thought. Got to be more careful.[&o]

Later
Kelly

Attached Thumbnails

Greg Norman said, \"Happiness is a long walk with a putter.\" Obviously he never flew a P-51 Mustang.

RE: 162

Ok, I've been working on the left wing panel for the last few days, This is kind of like a re-run

I will post a few pics of how I make up my wing skins. MAybe this will be helpfull to someone. I learned this from Jack Devine's website years ago.

I don't trim my sheets. Most of the time you can turn the bow the same way and get a tight joint. Use masking tape to hold the sheets together. Flip the sheet over and hang them off the edge of the table. Add the glue to the joint that's open and move it up one sheet. As you do this the sheets on the table will lye flat, squezzing the excess glue out. Them wipe the excess off with a towel. Let it sit for a few hours and you have wing skins.

A good friend of mine gave me a great tip. Sand the sheet joints smooth on the table, because it's easier and you get better results than sanding after it's applied.

Last couple of pics is of the wing assembled. The table it's on is 11 feet long.
Later,
Kelly

Attached Thumbnails

Greg Norman said, \"Happiness is a long walk with a putter.\" Obviously he never flew a P-51 Mustang.

RE: 162

Very nice build you've got going here Kelly! [sm=thumbs_up.gif] I especially like the fact that you're cutting out all of your own parts instead of using laser fried parts! Although they can be very accurate I don't care for the look of the burnt edges of laser cut wood!

RE: 162

Hey Winglift, Here is what I used to attach the templet to the wood. Just give it a light pass and it sticks pretty good. Seperation is easy and the adhesive isn't noticable on the wood afterwards. You can stack as many sheets as you need. I had to make two of each rib.

Also, 3M makes #77 spray and I found some really cheap stuff the other day for $4 a can but haven't tried it yet. I believe the NAPA spray was $10.

Hope this helps,
Kelly

Attached Thumbnails

Greg Norman said, \"Happiness is a long walk with a putter.\" Obviously he never flew a P-51 Mustang.

RE: 162

very nice work! One technique i was shown for making wing skins, is to join the sheets of balsa with contact cement. Works pretty good and is a fairly quick procedure providing that the sheets are all lined up and fitted properly.